springcloud gateway搭建

Spring Cloud Gateway的核心包是Spring Cloud Starter Gateway,截止发文maven仓库最新版是3.0.4,如下图：

springcloudstartergateway-maven

图中可以看到Spring Cloud Starter Gateway-3.0.4依赖了gateway所需要的包版本，要求的springboot版本是2.5.5，所以只要引入2.5.5版本的springboot和3.0.4版本的Spring Cloud Starter Gateway包就可以了。

pom.xml:(不需要的jar包可以不引入）

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>
    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.5.5</version>
        <relativePath />
    </parent>
    <groupId>com.zhaohy</groupId>
    <artifactId>springcloudGateway</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <name>springcloud-gateway</name>
    <description>Demo project for Spring Boot</description>
    <packaging>jar</packaging>

    <properties>
        <java.version>1.8</java.version>
    </properties>

    <dependencies>

        <!--springboot热部署 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-devtools</artifactId>
            <optional>true</optional>
        </dependency>

        <!--JSON依赖 -->
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.58</version>
        </dependency>

        <dependency>
            <groupId>commons-fileupload</groupId>
            <artifactId>commons-fileupload</artifactId>
            <version>1.4</version>
        </dependency>
        <dependency>
            <groupId>commons-io</groupId>
            <artifactId>commons-io</artifactId>
            <version>2.6</version>
        </dependency>
        
        <dependency>
            <groupId>net.sf.flexjson</groupId>
            <artifactId>flexjson</artifactId>
            <version>3.3</version>
        </dependency>
        
        <dependency>
            <groupId>nl.bitwalker</groupId>
            <artifactId>UserAgentUtils</artifactId>
            <version>1.2.4</version>
        </dependency>
        
        <dependency>
            <groupId>com.auth0</groupId>
            <artifactId>java-jwt</artifactId>
            <version>3.10.2</version>
        </dependency>
        
        <!-- httpClient用到的jar包 -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpcore</artifactId>
            <version>4.4.13</version>
        </dependency><dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpclient</artifactId>
            <version>4.5.12</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.apache.httpcomponents/httpmime -->
        <dependency>
            <groupId>org.apache.httpcomponents</groupId>
            <artifactId>httpmime</artifactId>
            <version>4.5.12</version>
        </dependency>
        
        <dependency>
            <groupId>net.coobird</groupId>
            <artifactId>thumbnailator</artifactId>
            <version>0.4.14</version>
        </dependency>
        
        <!-- https://mvnrepository.com/artifact/org.springframework.cloud/spring-cloud-starter-gateway -->
        <dependency>
            <groupId>org.springframework.cloud</groupId>
            <artifactId>spring-cloud-starter-gateway</artifactId>
            <version>3.0.4</version>
        </dependency>
        
    </dependencies>

    <build>
        <plugins>
            <plugin>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-maven-plugin</artifactId>
            </plugin>
        </plugins>
    </build>

</project>

新建application.yml:

server:
  port: 8081
spring:
  cloud:
    gateway:
      routes:
      - id: test_route
        uri: https://www.baidu.com
        predicates:
        #访问路径：localhost:8081?url=baidu 代表跳转到www.baidu.com
        #url带有baidu的自动跳转到https://www.baidu.com
        - Query=url,baidu
      - id: path_route
        uri: https://www.baidu.com
        predicates:
       #访问localhost:8081/s跳转到https://www.baidu.com/s
        - Path=/s
      - id: query_route
        uri: https://www.baidu.com
        predicates:
        #访问路径：localhost:8081?url=green 代表跳转到www.baidu.com
        #查询条件带有green的自动跳转到https://www.baidu.com
        - Query=green

启动springboot项目，url访问http://localhost:8081/s 就被转发到了https://www.baidu.com/s，url访问http://localhost:8081?url=baidu被转发到了 https://www.baidu.com，url访问http://localhost:8081？green=id，（访问参数里含有green）,也被转发到了百度首页。

更多gateway转发规则可以去官网详查：
https://docs.spring.io/spring-cloud-gateway/docs/current/reference/html/
或者看这两篇博文觉得也讲的挺细的：
https://www.jianshu.com/p/c8ac84e820cc
https://www.cnblogs.com/crazymakercircle/p/11704077.html

nginx和gateway的区别：
nginx一般作为前端的网关，在最外面一层，对外的，gateway一般作为后台服务器之间不经过前端的用法，对内的。